A Syrian opposition leader called on world leaders to take "immediate action" to end government attacks on rebel-held suburbs of Damascus, amid reports that some 150 people have been killed in government airstrikes in the past 10 days.

The U.N. peacekeeping chief strongly denied on Wednesday allegations from the Philippines` army chief that Filipino peacekeepers in the Golan Heights were ordered to surrender their weapons to Islamist militants who had trapped them.

Around 270 Syrian rebels granted safe exit under a complex deal with President Bashar al-Assad`s forces are being held in Homs by the army after insurgents elsewhere failed to uphold their side of the agreement, Syrian officials said on Friday.

Fighting between al Qaeda`s Syria branch and a splinter group in eastern Syria has forced more than 60,000 people to flee their homes, emptied villages and killed scores of fighters, a monitoring group said.

Syrian soldiers entered eastern districts of the town of Yabroud, the last rebel bastion near the Lebanese border north of Damascus, on Saturday and advanced towards the main street, Al Mayadeen television said.

Light arms supplied by the United States are flowing to "moderate" Syrian rebel factions in the south of the country and US funding for months of further deliveries has been approved by Congress, according US and European security officials.

Syrian and international delegates were arriving in Switzerland on Tuesday on the eve of peace talks that few believe can succeed as the three-year-old civil war and geopolitical acrimony it has brought show no sign of abating.

Syrian President Bashar al-Assad`s regime could face war crimes charges in international court, after top war crime prosecutors claimed to have direct evidence of "systematic torture and killing" of about 11,000 detainees by his forces.